Final answer:
Sentences A (Planets have atmospheres) and C (Planets have defined orbits around stars) pertain to properties of planets. Sentences B (Objects that aren't planets have irregular shapes) and D (Objects that aren't planets may have moon-like companions) describe attributes typically associated with non-planetary objects.
Step-by-step explanation:
To categorize the sentences based on whether they describe planetary or non-planetary attributes, we should first understand the fundamental characteristics of planets and other celestial objects. Planets are celestial bodies that orbit a star and have cleared their orbit path of other debris. They also have sufficient mass for their gravity to maintain a nearly round shape and do not emit light of their own.
- A. Planets have atmospheres: This is a characteristic of planets, although the type and thickness of the atmosphere can vary widely from one planet to another.
- C. Planets have defined orbits around stars: This is one of the key criteria used to classify a celestial body as a planet.
On the other hand, objects that are not classified as planets, such as asteroids and comets, often have different attributes including irregular shapes and lacking clear atmospheric layers.
- B. Objects that aren't planets have irregular shapes: This attribute is generally true for smaller celestial objects that lack the gravitational force necessary to pull themselves into a spherical shape.
- D. Objects that aren't planets may have moon-like companions: This is true for many non-planetary objects that can have smaller objects in orbit around them.
A and C describe planetary attributes, having atmospheres and defined orbits around stars, while B and D refer to attributes of non-planetary objects, having irregular shapes and possibly moon-like companions.